Move more files into the content namespace.

base/threading/thread_restrictions.h

Index: base/threading/thread_restrictions.h
===================================================================
--- base/threading/thread_restrictions.h	(revision 147462)
+++ base/threading/thread_restrictions.h	(working copy)
@@ -21,7 +21,6 @@
 class GpuChannelHost;
 class MetricsService;
 class NativeBackendKWallet;
-class RenderWidgetHelper;
 class TestingAutomationProvider;
 class TextInputClientMac;
 
@@ -42,6 +41,7 @@
 namespace content {
 class BrowserGpuChannelHostFactory;
 class GLHelper;
+class RenderWidgetHelper;
 }
 namespace dbus {
 class Bus;
@@ -159,8 +159,8 @@
  private:
   // DO NOT ADD ANY OTHER FRIEND STATEMENTS, talk to jam or brettw first.
   // BEGIN ALLOWED USAGE.
+  friend class content::RenderWidgetHelper;
   friend class ::HistogramSynchronizer;
-  friend class ::RenderWidgetHelper;
   friend class ::TestingAutomationProvider;
   friend class SequencedWorkerPool;
   friend class SimpleThread;